Method of constructing door panels



P M. s. RA-NDALL 1,998,590

METHOD OF CONSTRUCTING DOOR PANELS Filed Jan. 11, 1932 INVENTORS77red1'f/2 '5. Fonda/i wm ATTORNEYS.

Patented Apr. 23, 1935 UNITED. STATES PATENT OFFICE Woodall IndustriesIncorporated, Detroit,

Mich., a corporation of Michigan Application January 11, 1932, SerialNo. 585,901

1 Claim.

My invention relates to laminated water proof panels particularlyintended for automobile interior trim use and to the method of theirmanufacture.

5 Trim panels for automotive vehicle bodies have in the past been madeof materials so formed and arranged as to provide an imitation of otherand more expensive materials. One of the most common methods ofconstructing trim panels has been to utilize a backing of fiber board inconjunction with a layer of upholstery of any desired type which wassecured to the fiber board backing. Securing a layer of upholsterymaterial, or trim fabric, over a plane fiber board backing was notentirely satisfactory. Various disadvantages were attendant upon thistype of construction.

If the fabric were stretched tightly over the board it was difiicult toavoid the disastrous effect of moisture to which such panels aresubject. Moisture tended to produce warpage or buckling of the panelboard and as a result the trim fabric stretched, wrinkled, or gathered,producing an unsightly unattractive appearance.

It was also customary to provide a layer of 25 so-called wadding betweenthe fiber board backing and the trim material, not only to overcome thisdifiiculty but to give an upholstered effect to the finished panel. Thiswadding was of felt,

cotton batting, or other such suitable substancel The trim materialwhich covered the wadding was generally stitched to the fiber boardbacking at various points for the purpose of retaining the wadding inplace and preventing its collection in lumps. Stitching also served togive the panel a decorative effect by breaking up what would otherwisebe a normally plain surface.

This operation of providing a layer of wadding and subsequentlystitching the trim material to the backing added materially to the costof pro- 40 duction and an object of this invention is to eliminate thenecessity therefor while at the same time securing equally satisfactoryresults insofar as maintaining a permanently smooth and decorativetrim-surface and providing an effect trim panel an effect of depth,body, and elegance which could not be secured by simply superimposing alayer of trim material upon a plane cardboard backing. My inventionlooks toward the provision of such an effect without the use of waddingor stitching and in a cheap and inexpensive construction.

In thecarrying out of my invention I employ as a backing or foundationfor my improved panel a fiber board possessing thermoplastic and waterresistant characteristics. Such material is capable of being embossed toprovide any desired surface contour and is capable of retaining theshape so imparted to it throughout its normal life. A fiber board havinga substantial content of asphaltum has been found very suitable for thispurpose. By so embossing the backing to produce a desired surfacecontour, the effect of the wadding on the exterior surface of the trimmaterial may be reproduced in all its detail, the embossing being of anature to reproduce the effect of normal upholstery.

While it is possible to secure the trim material to such a backing afterthe latter has been embossed to produce the desired surface contour,this practice is attended with dificulties and it is not my intention soto do. I prefer to first associate the trim material with thethermoplastic cardboard backing by a suitable adhesive and tosubsequently emboss the entire composite structure. Several importantadvantages attend this procedure, one being that a continuous strongbond between the trim material and the backing throughout the entireadjacent surfaces of the two may more readily be secured in this 35manner and that the fabric and adhesive are molded, as it were, with andinto the shaped contour of the foundation board so as to provide asmooth exposed surface throughout the entire exposed face of the panelas if every portion had been carefully stretched by hand and in asimilar manner secured in position.

It is important that the adhesive be in a viscous condition at the timethe composite material is embossed to reproduce the "Wadding effect.When the adhesive is in its viscous condition it is capable of flowing,upon being subjected to the pressure of the embossing operation, withsufficient freedom to insure a continuous adhesive bond over the entireadjacent surface, as distinguished from intermittent and scatteredpoints of attachment of the materials.

There are several ways of insuring a satisfactory flow of the adhesiveduring the embossing operation. One of them is to subject the compositematerial, the backing with the trim material spread thereover upon alayer of adhesive, to the embossing operation shortly after the trim hasbeen spread over the backing. By so doing the adhesive will not have hadtime to dry and crystallize, but will still retain a certain amount ofits viscosity and flow with suflicient freedom for the purpose. Anotherprocedure, and this one is particularly adaptable for use in conjunctionwith thermoplastic material of the nature heretofore described, is tosubject the composite material to a certain amount of heat during theembossing operation.

The preferable manner of manufacturing the improved panel will now bedescribed in some detail in conjunction with the drawing wherein:

Fig. 1 is a side elevation of the semi-completed panel, partly brokenaway,

Fig. 2 is a fragmentary sectional elevation 11- lustrating one stage ofthe process, and

Fig. 3 is a section through 2-2 of Fig. 1.

A plane surfaced backing ID of thermoplastic material such as commercialK-B fiber board, which is a composition fiber board carrying asubstantial asphaltum content as a binder and water resistant agent, iscoated with a layer of a suitable adhesive l2. An adhesive should beused which does not have a tendency to bleed the asphalt or hinder fromwithin the sheet to the surface thereof and which would also serve as abarrier to prevent bleeding of binder from the board to the fabric suchas latex. A layer M of trim material of any suitable type is then spreadover the adhesive and the composite laminated panel structure so formedis then placed in the embossing dies and subjected simultaneously tosuch heat and pressure as is necessary to shape thesurface contour ofthe thermoplastic sheet as desired.

In the structure illustrated in the drawing, my composite panel has beenembossed to produce a series of decorative elevated portions 16. Thesemay be of any desired size and shape and create the same effect as ifthe backing had been provided with layers of wadding over theseparticular portions and the trim stitched to the backing through thewadding along the lines l8. This effect is possible only because theband between the backing and the trim produced by this particularprocess is sufficiently strong and continuous to retain the fabricclosely united to the backing over the entire area of the panel, alongthe lines of joinder l8 which simulate the stitch lines, and the planeexpanse 20 of the finished panel.

In the form illustrated a pocket depression 22 has been included in theembossed portion of the panel. The necessity of stitching along theperiphery of this pocket portion is also eliminated.

The result is a composite panel comprised of inexpensive componentmaterials securely and permanently united into a single composite panelpossessing all of the advantages, both as to appearance and structure,inherent in the wadded and stitched type of panel without thedisadvantage of wadding, cost of manufacture, or tendency of the waddingto deterioration. The overlapping edges of trim material may be foldedback and glued to the rear surface of the backing board, or they may becut off and a binding secured about the edges of the panel.

While as is hitherto stated, the individual materials and operationsinvolved in this invention are not necessarily of and in themselvesnovel, the use of the materials in the combination specified inconjunction with the steps indicated heretofore result in an extremelyinexpensive and suitable trim panel which is superior to the structurehitherto utilized and which is far less costly to produce.

I claim:

That method of manufacturing a laminated trim panel comprising applyingto the surface of a composition fiber board carrying an asphaltum bindera layer of moisture resistant adhesive neutral to the asphaltum contentof the board to form a barrier thereover sealing the asphalt in theboard against migration, spreading a sheet of fabric finish materialover the adhesive coated surface of the board, subjecting "the coveredboard to a forming operation employ- LEREDITH S. RANDALL.

